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My rendition of Squalodon calvertensis (Long-Snouted Shark Toothed Whale). Notice the large pectoral fins, reduced dorsal fin, mobile neck, the long beak, and the front teeth protruding from the jaw, creating small tusks.

Squalodons: The Details

General Overview

Squalodons lived from the early-middle Oligocene into the middle Miocene, roughly 33 to 14 million years ago. The squalodon genus belongs to the Odontocete Order, the toothed whales. Specifically it belongs to the Squalodontidae superfamily. This superfamily is named after the shark squallus, since its' cheek teeth superficially resemble the teeth of a squallus shark; hence the name "shark toothed whale".

The Squalodontidae superfamily contains three different groups of medium-sized (roughly 3 meters in length - 10 ft) shark toothed whales. They are the short-snouted shark toothed whales (prososqualodon), the medium-snouted shark toothed whales (phoberodon), and the long-snouted shark toothed whales. This last group contains the genus squalodon.

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Modern and Archaic Features - The Teeth

A strange mix of archaic and modern features characterizes these interesting prehistoric whales. One of the most noticeable archaic features of squalodons is their complex dentition. While other toothed whales were evolving simple conical teeth at this time, Squalodontidae retained their primitive teeth that their ancestors (the archaeocetis) had. For example their dentition is complex, their teeth are widely spaced apart, and their cheek teeth are triangular and serrated for grasping and cutting. An illustration of this similar archaeoceti dentition can be seen below.

Modern and Archaic Features - The Neck

Another archaic quality the Squalodontidae possess is their necks. The necks are more compressed than archaeoceti; however they were probably more mobile than the other "modern looking" toothed whales at the time. Finally, paleontologists believe the dorsal fins were larger than archaeocetis, but still somewhat reduced.

Modern and Archaic Features - Blowhole and Echolocation

Despite these ancient features on Squalodontidae, they also had a mix of modern characteristics. For example, their craniums were well compressed and their rostrums were telescoped outward. This compression moved the nostrils toward the top of the head, giving them a similar appearance to modern toothed whales. Finally, squalodon skulls show evidence for the first appearance of echolocation. An illustration of the changes can be seen below.

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Extinction and Fossil Occurrence

These strange looking creatures could be found throughout the world in the Oligocene and Miocene. However, squalodons became extinct in the middle of the Miocene and left no descendants. Now, occasionally one can find an isolated tooth or bone from one of these great beasts while beach combing along the shores below the Calvert Cliffs of Maryland, or searching the Miocene and Oligocene exposures in NC and SC.

Species
There are at least two species of squalodon found along the Atlantic Coastal deposits. They all look similar, but are different in size, and have slight differences in tooth morphology. Squalodon whitmorei (Dooley, 2005) is the largest species, and Squalodon calvertensis (Kellogg, 1923) is the slightly smaller species with a longer snout. There may be an additional undescribed species at the Calvert Cliffs of Maryland, and there are possibly other species of squalodon found in Europe (mainly Italy and France). Other species of squalodon have been found in Australia and New Zealand

Squalodon atlanticus is a common species name attributed to numerous specimens, however, S. atlanticus is probably invalid. For an excellent explanation, Dr. Alton Dooley (THE expert on Squalodons) has a good summary on the VMNH website here.

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Carrol, R. (1988). Vertebrate Paleontology and Evolution. NY: W.H. Freeman & Company.

Mchedlidze G.A.; Translated by Chakravarthy, R. (1984). General Features of the Paleobiological Evolution of Cetacea. New Delhi: Oxonian Press. Translated for Smithsonian Institution Libraries.

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Recommended Books

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The Walking Whales: From Land to Water in Eight Million Years
By: J. G. M. "Hans" Thewissen, 2014
This is a great book for learning about whale evolution. It's the most up to date book (2014), and has all of the recent discoveries over the past decade. Hans Thewissen gives a firsthand account of the fossil discoveries, from their origins as small land dwelling mammals to modern whales. He is also one of the leading researchers in the field of whale paleontology. This is a great book for if you are interested in understanding whale evolution. Check it out.

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Cetacean Paleobiology (TOPA Topics in Paleobiology)
by Felix G. Marx,? Olivier Lambert, and Mark D. Uhen, Copyright 2016

From Squalodons and Basilosaurus to Maiaicetus, this is it! A treatise on whale evolution complete with many of the new fossil discoveries and new genetic research! It covers the global cetacean fossil record, the move from land to sea, diversity in different time periods, evolutionary changes, and much much more! If you are crazy about the evolution of whales, you must have this! You can browse through the table of contents and select pages via the link.

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Squalodon Fossil Identification:

Isolated teeth cannont be identified to a species level. One needs skull material to determine an exact species of squalodon.

Below are fossil identification images for Squalodon:

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Squalodon Teeth

Squalodon Jaw Section

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Kellogg's Squalodon 1923 Plates

Kellogg first described Squalodon calvertensis from the Calvert cliffs in Maryland in 1923. His publication has identification plates for the partial specimens he described. Below are a few plates from his publication:
Kellogg, Remington. (1923). Description of two squalodonts recently discovered in the Calvert Cliffs, Maryland: and notes on the shark-toothed cetaceans. No. 2462 PP 1-69. April 24.

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Whales that are similar to Squalodons

In the Oligocene time period, 34 to 23 million years ago, early toothed whales were fairly common. There were different families that all had similar dentitions as the squalodon. However, by the start of the Miocene, around 23 million years ago, most had become extinct.

Fortunately, Oligocene sediments along coastal South Carolina are plentiful, formations like the Wando, Chandler Bridge, and Ashley formation periodically reveal new types of early whales. The Mace Brown Museum in Charleston has skulls of some of these unique fossils on display. Below are a few examples of these odd Oligocene whales.



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Sample Squalodon Fossils